docs: def _ref_covered_by_at_least_one_full_length_contig(nucmer_hits, percent_threshold, max_nt_extend):
          '''Returns true iff there exists a contig that completely
             covers the reference sequence
             nucmer_hits = hits made by self._parse_nucmer_coords_file.'''
          for l in nucmer_hits.values():
              for hit in l:
                  if ( (2 * max_nt_extend) + len(hit.ref_coords()) ) / hit.ref_length >= percent_threshold:
                      return True
          return False